Electron discharge device



Dec. l, 19959 w. c. .JOHNSON ET AL 2,915,667

ELECTRON DISCHARGE DEVICE 5 Sheets-Sheet 1 Filed Feb. l5, 1957 Dec. 1, 1959 w. c.. 1oHNsoN ETAL 2,915,667

ELECTRON DISCHARGE DEVICE Filed Feb. 13, 1957 S'SheebS-Sheet 2 lnsulatlve Material a mvENToRs WITNESSES- Warren C. Johnson 8| m AErvneasf F. Smart.

fm v ATTORNEY Dec. 1v, 1959 w. c. JOHNSON ETAL 2,915,667

ELECTRON DISCHARGE DEVICE Filed Feb. 13, 1957 3 Sheets-Sheet. 3

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United States Patent ELECTRON DISCHARGE DEVICE Warren C. Johnson and Ernest F. Smart, Horseheads Township, Chemung County, N .Y., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a `corporation of Pennsylvania Application February 13, 1957, Serial No. 640,008

7 Claims. (Cl. 313-265) This invention relates to electron discharge devices and, more particularly, to grid electrodes suitable for use in electron discharge devices.

One of the factors allowing the necessary short Wavelength operation for ultra-high frequency electron dischargedevices is the very small spacing between the electrodes. This small spacing results in a high transconductance-tocapacity ratio and'therefore allows high efciency to be obtained. For example, in receiving tubes for operation in the 1000 megacycle'region, the cathodeto-grid spacing may be about 0.001 inch. In order to accurately` control the spacing as much as possible, socalled frame grids have been developed in which a number. of grid lateral members are stretched across a grid frame resulting in a planar grid electrode. However, it is very difticult to maintain the `grid laterals under sufcient tension during operation to prevent them from becoming slack, being displaced inwardly or outwardly and thereby disrupting the delicate spacing required. Also, it has been found to be very diiicult to make a grid frame that is exactly planar. However, if the grid frame is not exactly planar, the grid laterals may become .slack with the above-mentioned disruption of the necessary accurate spacing.

Therefore, it is an object of this invention to provide an improved electron discharge device electrode structure.

It is another object to provide an improved electrode structure in which the electrode spacing may be accurately maintained.

It is a further object to provide an improved grid electrode suitable for maintaining accurate grid to cathode spacing.

It is an additional object to provide improved spacer members which in conjunction with an improved grid electrode maintain tension on the grid lateral members of the` grid electrode during operation of the electron discharge device. .f

It is still another object to provide amethod of positioning `a grid electrode in an electron discharge device so .that the grid laterals are under tension afterY the grid electrode is nally positioned...

f It is. a still further object to provide a grid electrode whichdue to mechanical deformation of the grid frame when the grid electrode is positioned causes the grid later; als to be under tensionA in the electron discharge device.

These and other objectscfcur invention will be apparent from the following description taken in accordance withy the accompanying drawing throughout which like reference characters indicate like parts, which drawingforms a part of this application and in which:

Figure 1 is a top sectional view of an electrode structure in which the grid electrode is constructed and positionedY in accordance with one embodiment of our invention;

Fig. 2`is `a side sectional view of Fig. l take along line Il-II;

Fig. 3'is a top view of a rst insulative spacer mem- ICC ber constructed according to one embodiment of our invention;

Fig. 4 is a top View of a second insulative spacer member constructed according to one embodiment of our invention;

Fig.l 5 is a front View of a grid electrode constructed in accordance with one embodiment of our invention;

Fig; 6 is a top view of the electrode shown iny Fig. 5;

Fig. 7 is a top View of an electrode similar to that shown in Fig. 5 according to one embodiment of our invention;

Fig. 8 is a top View of a grid electrode constructed in accordance with another embodiment of our invention.

Fig. 9 is a top View of a grid electrode constructed in accordance with ano-ther embodiment of our invention;

Fig. 10 is a front view of a rst insulative spacer miember constructed in accordance with one embodiment of our invention; and

Fig. l1 is a front view of a second insulative spacer member constructed in accordance withI one embodiment of our invention. Y

In general, our invention involves forming a frame grid electrode in such a manner Kthat it may be mechanically deformed upon insertion into an electrode mount of an electron discharge' device so that the grid lateral mem-bers are under an additional strain or tension which tends to keep them taut and in their original plane, thereby providing accurate spacing between the grid and the cathode and between the grid and the anode or other grid electrodes.

In Fig. l thereis shown a top sectional view of an electron discharge device which is suitable for use in our invention. A cathode 2.5 includes a cathode sleeve member 11 and a heater member 13 which is connected by means of heater connectors 15 to the heater leads 17. A cathode tab 33 connects the cathode sleeve member 11 to; the cathode' lead 35. 'An anode member 19 having anode rear portions 20 and anode side portions 22 is connectedby means of an anode lead connector 21't0 three anode leads 23 which in this particular embodiment are arranged in a single plane. Between the anode 19 and the cathode 25' thereisl positioned a grid electrode 27 which is connectedv by means of a grid lead connect/or 29 tol three grid leads 31 which,l in this embodiment, are also arranged in a singleV plane; Y As can be seen, the two heater le'ads 17 and the cathode, lead 35 are also in a single plane which is parallel to the `plane of the grid leads 31 and the anode' leads 23. While our invention maybe utilized with other lead structures, the particular embodiment shown in Fig. 1 hasr the advantage with ultra-high frequency devices that the lead length is minimized between the circuit and tube elements and that this particular lead arrangement may be conveniently connected to transmission lines. Also, the three leadsV to the anode 19`and the three leads to the grid electrode 27 reduce' the lead inductances, which is extremely de# sirable. Ascan be seen in Fig. l, the grid electrode 27 includes a grid frame member 37 and grid lateral members 39, the structure of which will be discussed in more detail below. An insulative envelope member 41 en-V closes the electrode structure. To avoid unnecessary confusion in the drawing, the insulating spacer members discussed below and shown in Figs. 2, 3, l4, 9 and lO are'not shown in Fig. l.

In Fig. 2, there is shown' a side sectional view of the electron discharge device shown in Fig. l, taken along lines II-IL The cathode 25, the grid electrode 27 and the anode 19 are shown with the heater leads 17, grid leads 31 and the anode leads 23. Also shown are the anode lead connector 21, the grid lead connector 29., the cathode tab 33 and the heater connectors 15. The elements of ther tube' are-positioned and spaced by spacer amasar members 43 which will be discussed in more detail below. The bottom portion 45 of the envelope 4i of the electron discharge device, through which the lead members extend, is known as the stem or button.

The insulative spacer members 43 such as those shown in Fig. 2 are more clearly shown in Figs. 3 and 4. In Fig. 3 a first spacer member 47 made of an insulative material such as mica, ceramic or hard glass, is shown including a number of peripheral locating protrusions 49 and a number of apertures. In this particular embodiment these apertures include two anode first ear apertures 5i, a grid locating aperture 53 and a cathode locating aperture 55. The anode ear apertures 51 include an anode first ear bearing portion 57 and the grid locating aperture 53 includes side arm bearing portions 59. In this particular embodiment, the first spacer member 47 of Fig. 3 cooperates with the second spacer member 67 shown in Fig. 4 which includes two anode second ear apertures 61, two anode first ear bearing surfaces 63 and two grid side arm bearing surfaces 65.

The grid electrode shown in Figs. l and 2 is shown in more detail in Figs. 5, 6, 7 and 8. In Fig. 5 is shown a front view of a grid electrode 27 constructed according to one embodiment of our invention including a grid frame member 37 having two side arm members 69 and two bent side arm connecting members 71. A plurality of grid lateral members 39 have been attached to the side arm members 69. In Fig. 6, there is shown a top view of a grid electrode 27 similar to that shown in Fig. 5 including the grid frame member 37, the side arm members 69, the side arm connecting members 71 and the grid lateral members 39. As can be seen, the side arm members 69 have two substantially parallel surfaces, namely a first surface 73 and a second surface 75. Also, each side arm member 69 has an inner portion 77 and an outer portion 79. The grid frame members 37 may be made of materials such as Kovar, tungsten or molybdenum and the grid lateral members 39 may be made of materials such as tungsten, molybdenum or titanium. The grid electrodes may be made in a number of ways, but one which we have found to be most satisfactory is to position them on a drum mandrel and wind the grid lateral wires around the drum mandrel in such a way as to provide the desired number of grid laterals with the desired spacing. The grid laterals may then be silver soldered to the grid frame members in a furnace utilizing a suitable atmosphere, such as hydrogen, to prevent oxidation. Other methods such as gold soldering or glass bonding may also be used in joining the grid laterals to the grid frame members. After the grid laterals are attached to the side arm members, the completed grid electrodes are separated from each other by a cutting operatlon.

In Fig. 7, there is shown a top view of a grid electrode similar to that shown in Fig. 5. As can be seen, there is a slight difference between the grid electrodes shown in Fig. 6 and Fig. 7, namely that shown in Fig. 6 has its side arm members 69 in the same plane while that shown in Fig. 7 has its side arm members 69 bent slightly forward. We will first consider the case in which the grid electrode similar to that shown in Fig. 7 is utilized. The cathode 25, the grid electrode 27, similar to that shown in Fig. 7, and the anode electrode 19 are possitioned with first insulative spacer members 47 at the top and the bottom of the electrodes so that the anode first ears, which are located on the anode rear portions 20, are inserted into the anode rst ear apertures Sli and the cathode 25 is inserted into the cathode locating aperture 55. The grid electrode 27 is inserted into the grid locating aperture 53 but because the side arm members 69 have been bent slightly forward they will not rest fiush against the grid side arm bearing portions 59 of the grid locating aperture 53. Then the top and bottom second insulative spacer members 67 are pressed into place against the top and bottom first spacer members, respectively, so that the anode first ear bearing surfaces 63 rest against the anode first ear members and so that the grid side arm bearing surfaces 65 push against the grid side arm members 69 in such a manner as to force the grid side arm members 69 into a single plane similar to the position shown in Figs. 1 and 6. Therefore, it can be seen that the second spacer member 67 exerts a first force on the inner portion 77 of the side arm members 69 in a direction substantially from the second surface 75 toward the first surface 73 of the side arm members 69. Also, the first spacer member 47 exerts a second force against the outer portion 79 of the side arm member 69 in a direction substantially from the first surface 73 toward the second surface 75. As the side arm members 69 are straightened, the grid lateral members 39 undergo a tension which will keep them in the same plane and maintain accurate spacing.

In prior art electron discharge devices, grid electrodes were attempted to be constructed so that the side arm members 69 would be in the same plane. However, as this was extremely ditiicult to do, when the grid electrodes 27 were positioned in the electron discharge device, the wires tended to be distorted inwardly or outwardly and therefore the delicate spacing was disrupted. As can be seen, the grid electrode 27 and insulative spacer members 47 and 67, constructed in accordance with our invention and used in accordance with our invention, maintain a continuous strain upon the grid laterals 39 in such a manner as to keep them taut at all times.

In another embodiment of our invention in which the same principle is used, a first insulative spacer member 81 such as that shown in Fig. 10 is constructed. As can be seen, this spacer member 81 is very similar to that shown in Fig. 3, with the exception that the side arm bearing portions 83 are slanted in a backward manner from the inner to the outer portions. Also, in Fig. 11 there is shown a second insulative spacer member 85 similar to that shown in Fig. 4 except that the side arm bearing surfaces 87 are slanted in a backward manner from the inner to the outer portions. A grid electrode 27 similar to that shown in Fig. 6 is used in the assembly of an electron discharge device with the insulative spacer members 81, 85 shown in Figs. 10 and 11. As can be seen, when the second insulative spacer member 85 shown in Fig. 11 is positioned, a rst force will be exerted against the inner portions 77 of the side arm members 69 in a direction from the second surface 7S to the first surface 73 and a second force will be directed against the outer portions 79 of the side arm members 69 in a direction from the first surface 73 to the second surface 75. The side arm members 69 will therefore be distorted in a manner which will result in a grid electrode 27 similar to that shown in Fig. 8 in which the side arm members 69 are bent backwards. This backward bending or deformation of the side arm members 69 has the effect of keeping the grid lateral members 39 under a tension which has the desirable result of keeping the grid lateral members 39 taut and in the same plane. In Figs. 7 and 8, the amount the side arm members 69 is bent is exaggerated for purposes of illustration. Actually, in a grid electrode 27 having a width of approximately 0.375 inch, the distance that the side arm members would be bent either backwardly or forwardly would be between 0.003 inch and 0.005 inch.

It may sometimes be desirable to place a grid electrode 27 similar to that shown in Fig. 8 in an electron discharge device. In order to use available spaces and to prevent the necessity of designing new spacers, an appendant member 72 may be attached to the grid electrode 27 as shown in Fig. 9. In this particular embodiment, the appendant member 72 is attached to the first surface 73 and the grid lateral members 39 and is in the form of a metallic shim member. Of course, other forms, such as a wire, may be used, and the appendant members '72 Amay be positioned -in other portions` of the vside arm member 69, if desired. We have found that rsuitable materials for the appendant member 72 include nickel and molybdenum.

With a grid electrode 27 such as shown in Fig. 9, a fixed insulative spacer member 47, such as that shown in Fig. 3, may be used in conjunction with a second spacer member 85 such as that shown in Fig. 11. Also, a first insulative spacer member 81 such as that shown in Fig. 10, may be used inl conjunction with a second insulative spacer memberv similar to that used in Fig. 1l, but with the side arm bearing surfaces 87 having a little more backward slant than shown in Fig. 11, in order to allow the side arm members 69 to be forced backwards enough to keep the grid lateral members 39 taut. The same forces and principles apply in connection with this embodiment as with the other embodiments shown.

In the particular embodiments shown, two upper spacer members and two lower spacer members have been used. It is, of course, within the scope of our invention to use only one upper spacer member and one lower spacer member and to have them constructed in such a manner that the grid apertures in the single spacer members will maintain the grid electrodes 27 in a deformed position after the side arm members 69 are inserted into the grid apertures. In this case, the side arm members 69 would have to be distorted slightly before insertion into the grid apertures. The particular embodiments shown in the subject application have the advantage that they are more adaptable for use in automatic production methods.

It is therefore seen that in general our invention nvolves positioning side arm members 69 of frame grid electrodes 27 in the apertures of spacer members in such a manner that the side arm members 69 are distorted so that the grid laterals 39 are always maintained in a taut position. In the particular embodiments shown, a first force has been exerted on the inner portions 77 of the side arm members 69 in a forward direction (that is, in a direction from the second surface 75 to the first surface 73) and a second force has been exerted on the outer portion 79 of the side arm members in a backward direction (that is, from the first surface 73 toward the second surface 75).

While the present invention has been shown in a few forms only, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit and scope thereof.

We claim as our invention:

1. An electron discharge device having a cathode, an anode, a grid electrode between said cathode and said anode, and a plurailty of apertured insulative spacer members, said grid electrode having a plurality of grid lateral members and a grid frame member having two side arm members, said grid lateral members being attached to said side arm members, said grid electrode being positioned within at least one aperture of said insulative spacer members, said apertures being of a configuration such that a force is exerted uponl said side arm members so that said grid lateral members are under tension and are maintained in a taut position.

2. An electron discharge device having a cathode, an anode, a grid electrode between said cathode and said anode, and a plurality of apertured insulative spacer members, said grid electrode having a plurality of grid lateral members and a grid frame member having two side arm members, said side arm members each having a first surface and a second surface, said grid lateral members being attached to said first surface of said side arm members, said side arm members having an outer portion and an inner portion, said grid electrode being positioned within at least one aperture of said insulative spacer members, said aperture being of a configuration such that a first force is exerted upon said inner portion in a direction substantially toward said first surface from sai'd second surface and a second force :is exerted upon said outer portion in a direction substantialy toward said second surface from said first surface so that said grid one first spacer member and at least one second spacer l member, said grid electrode having a plurality of grid lateral members and a grid frame member having.two side arm members, said grid lateral members being attached to said side arm members, said first spacer member having a grid locating aperturetherein, a portion of `the edge of said grid locating aperture constituting a grid side armbearing portion, said first spacer member having a plurality of anode ear apertures therein, a portion `of the edge of said anode ear aperture constituting an anode ear bearing portion, said second spacer member having a grid side arm bearing surface and an anode ear bearing surface, said side arm members of said grid electrode being positioned within said grid locating aperture, said anode ear members being positioned Within said anode ear apertures, said second spacer member being positioned so that said anode ear bearing surface forces said anode ear against said anode ear bearing portion, said grid side arm bearing surface forcing said grid side arm against said grid side arm bearing portion so that a force is exerted upon said side arm members in such a manner that said grid lateral members are under tension and are maintained in a taut position.

4. An electron discharge device having a cathode, an anode having a plurality of anode ear members, a grid electrode between said cathode and said anode and a plurality of insulative spacer members including at least one first spacer member and at least one second spacer member, said grid electrode having a plurality of grid lateral members and a grid frame member having two side arm members, said side arm members each having a first surface and a second surface, said grid lateral members being attached to said first surface of said side arm members, said side arm members having an outer portion and an inner portion, said first spacer member having a grid locating aperture therein, a portion of the edge of said grid locating aperture constituting a grid side arm bear-v ing portion, said first spacer member having a plurality of anode ear apertures therein, a portion of the edge of each of said anode ear apertures constituting an anode ear bearing portion, said second spacer member having two grid side arm bearing surfaces and a plurality of anode ear bearing surfaces, said grid side arm members being positioned within said grid locating aperture, said anode ear members being'positioned within said anode ear apertures, said second spacer member being positioned so that said anode ear bearing surfaces force said anode ear members against said anode ear bearing portions, said second spacer member also being positioned so that said grid side arm bearing surfaces force said grid side arm members against said grid side arm bearing portions so that a first force is exerted upon said inner portion in a direction substantially toward said first side arm surface from said second side arm surface and a second force is exerted upon said outer portion of said side arm member in a direction substantially toward said second side arm surface from said first side arm surface so that said grid lateral members are under tension and are maintained in a taut position.

5. A method of forming and tensioning a grid electrode, said method including the steps of forming a grid frame member having side arm members, attaching grid lateral wires to said side arm members to form a grid electrode, inserting said grid electrode in a plurality of apertured insulative spacer members so that said apertured insulative spacer members exert a force upon said grid electrode thereby deforming said grid frame member in such a manner as to increase the tension of said grid lateral members and maintain said grid lateral members in a taut position.

6. A method of forming and tensioning a grid electrode, said method including the steps of forming a grid frame member having side arm members, said side arm memers each having a first surface and a second surface, each side arm member having an outer portion and an inner portion, attaching grid lateral members to said iirst surface of said side arm members to form a grid electrode, inserting said grid electrode in a plurality of apertured insulative members so that a first force is exerted upon said inner portion in a direction substantially toward said first surface from said second surface, and a second force is exerted upon said outer portion in a direction substantially toward said second surface from said first surface, said first and second forces operating to deform said grid frame member so that said grid lateral members are vunder tension and are maintained in a taut position.

7. A method of forming and tensioning a grid electrode, said method including the steps ofy forming a grid frame member having side arm members, attaching to said side arm members a plurality of grid lateral wires, andpositioning said side arm members in apertures provided in a plurality of insulating spacer members in such a manner that said grid frame member is deformed so that said grid lateral wires are maintained in a taut position.

References Cited in the file of this patent UNITED STATES PATENTS 2,460,120 Bondley Jan 25, 1949 2,481,202 Dale Sept. 6, 1949 2,527,166 Walsh Oct. 24, 1950 2,621,303 Law Dec. 9, 1952 2,624,100 Foulkes Ian. 6, 1953 2,678,486 Chick et a1 v May 18, 1954 2,704,879 Diggle Mar. 2,9, 1955 

